## Can PHP Functions Be Both Recursive and Anonymous?

Implementing Anonymous Recursive Functions in PHP

When embarking on the task of crafting recursive functions in PHP, one might aspire to shroud them with anonymity. However, a pitfall presents itself when attempting to pass the function name as an argument to itself, as demonstrated in the code below.

<code class="php">$factorial = function( $n ) use ( $factorial ) {
    if( $n <= 1 ) return 1;
    return $factorial( $n - 1 ) * $n;
};
print $factorial( 5 );</code>

This endeavor will prove futile, leaving you with a lingering question: can PHP functions be both recursive and anonymous?

The answer lies in understanding the mechanics of variable referencing. To establish a recursive connection, the function must hold a reference to itself. This can be achieved by passing the function as a reference using the '&' operator. Below is an example of how this modification can unblock the anonymous recursion:

<code class="php">$factorial = function( $n ) use ( &$factorial ) {
    if( $n == 1 ) return 1;
    return $factorial( $n - 1 ) * $n;
};
print $factorial( 5 );</code>

With this adjustment in place, the PHP function transcends the boundaries of anonymity and seamlessly wields its recursive powers.

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